Detailed Description

Analog comparator (ACMP) Peripheral API.

The Analog Comparator is used to compare the voltage of two analog inputs, with a digital output indicating which input voltage is higher. Inputs can either be one of the selectable internal references or from external pins. Response time and thereby also the current consumption can be configured by altering the current supply to the comparator.

The ACMP is available down to EM3 and is able to wakeup the system when input signals pass a certain threshold. Use ACMP_IntEnable to enable an edge interrupt to use this functionality.

Here is an example of how to use the em_acmp.h API for comparing an input pin to an internal 2.5V reference voltage.

/* The ACMP is a high-frequency peripheral so we need to enable
 * both the HFPER clock and the ACMP0 clock. */
CMU_ClockEnable(cmuClock_HFPER, true);
CMU_ClockEnable(cmuClock_ACMP0, true);
/* Initialize with default settings. */
ACMP_Init_TypeDef init = ACMP_INIT_DEFAULT;
init.enable = false;
ACMP_Init(ACMP0, &init);
/* Setup the two channels to compare. The first argument is the negative
 * channel and the second argument is the positive channel.
 *
 * Here we compare channel 0 with the 2.5 V internal reference. When
 * channel 0 is lower than 2.5 V then the ACMP output is 0 and when
 * channel 0 voltage is higher than 2.5 V then the ACMP output is 1. */
ACMP_ChannelSet(ACMP0, acmpChannel2V5, acmpChannel0);
/* To be able to probe the output we can send the ACMP output to a pin.
 * The second argument to this function is the pin location which is
 * device dependent. */
ACMP_GPIOSetup(ACMP0, 0, true, false);
/* Finally we enable the ACMP. */
ACMP_Enable(ACMP0);

Note: The ACMP can also be used to compare two separate input pins.

The ACMP also contains specialized hardware for capacitive sensing. This module contains the function ACMP_CapsenseInit for initializing the ACMP for capacitive sensing and the function ACMP_CapsenseChannelSet for selecting the current capsense channel.

For applications that require capacitive sensing it is recommended to use a library like cslib which is provided by Silicon Labs.

Data Structures
struct	ACMP_CapsenseInit_TypeDef

struct	ACMP_Init_TypeDef

Macros
#define	ACMP_CAPSENSE_INIT_DEFAULT

#define	ACMP_INIT_DEFAULT

Enumerations
enum	ACMP_CapsenseResistor_TypeDef { acmpResistor0 = _ACMP_INPUTSEL_CSRESSEL_RES0, acmpResistor1 = _ACMP_INPUTSEL_CSRESSEL_RES1, acmpResistor2 = _ACMP_INPUTSEL_CSRESSEL_RES2, acmpResistor3 = _ACMP_INPUTSEL_CSRESSEL_RES3 }

enum	ACMP_Channel_TypeDef { acmpChannel0 = _ACMP_INPUTSEL_NEGSEL_CH0, acmpChannel1 = _ACMP_INPUTSEL_NEGSEL_CH1, acmpChannel2 = _ACMP_INPUTSEL_NEGSEL_CH2, acmpChannel3 = _ACMP_INPUTSEL_NEGSEL_CH3, acmpChannel4 = _ACMP_INPUTSEL_NEGSEL_CH4, acmpChannel5 = _ACMP_INPUTSEL_NEGSEL_CH5, acmpChannel6 = _ACMP_INPUTSEL_NEGSEL_CH6, acmpChannel7 = _ACMP_INPUTSEL_NEGSEL_CH7, acmpChannel1V25 = _ACMP_INPUTSEL_NEGSEL_1V25, acmpChannel2V5 = _ACMP_INPUTSEL_NEGSEL_2V5, acmpChannelVDD = _ACMP_INPUTSEL_NEGSEL_VDD, acmpChannelDAC0Ch0 = _ACMP_INPUTSEL_NEGSEL_DAC0CH0, acmpChannelDAC0Ch1 = _ACMP_INPUTSEL_NEGSEL_DAC0CH1, acmpChannelCapSense = _ACMP_INPUTSEL_NEGSEL_CAPSENSE }

enum	ACMP_HysteresisLevel_TypeDef { acmpHysteresisLevel0 = _ACMP_CTRL_HYSTSEL_HYST0, acmpHysteresisLevel1 = _ACMP_CTRL_HYSTSEL_HYST1, acmpHysteresisLevel2 = _ACMP_CTRL_HYSTSEL_HYST2, acmpHysteresisLevel3 = _ACMP_CTRL_HYSTSEL_HYST3, acmpHysteresisLevel4 = _ACMP_CTRL_HYSTSEL_HYST4, acmpHysteresisLevel5 = _ACMP_CTRL_HYSTSEL_HYST5, acmpHysteresisLevel6 = _ACMP_CTRL_HYSTSEL_HYST6, acmpHysteresisLevel7 = _ACMP_CTRL_HYSTSEL_HYST7 }

enum	ACMP_WarmTime_TypeDef { acmpWarmTime4 = _ACMP_CTRL_WARMTIME_4CYCLES, acmpWarmTime8 = _ACMP_CTRL_WARMTIME_8CYCLES, acmpWarmTime16 = _ACMP_CTRL_WARMTIME_16CYCLES, acmpWarmTime32 = _ACMP_CTRL_WARMTIME_32CYCLES, acmpWarmTime64 = _ACMP_CTRL_WARMTIME_64CYCLES, acmpWarmTime128 = _ACMP_CTRL_WARMTIME_128CYCLES, acmpWarmTime256 = _ACMP_CTRL_WARMTIME_256CYCLES, acmpWarmTime512 = _ACMP_CTRL_WARMTIME_512CYCLES }

Functions
void	ACMP_CapsenseChannelSet (ACMP_TypeDef *acmp, ACMP_Channel_TypeDef channel)
	Sets the ACMP channel used for capacative sensing. More...

void	ACMP_CapsenseInit (ACMP_TypeDef acmp, const ACMP_CapsenseInit_TypeDef init)
	Sets up the ACMP for use in capacative sense applications. More...

void	ACMP_ChannelSet (ACMP_TypeDef *acmp, ACMP_Channel_TypeDef negSel, ACMP_Channel_TypeDef posSel)
	Sets which channels should be used in ACMP comparisons. More...

void	ACMP_Disable (ACMP_TypeDef *acmp)
	Disables the ACMP. More...

void	ACMP_Enable (ACMP_TypeDef *acmp)
	Enables the ACMP. More...

void	ACMP_GPIOSetup (ACMP_TypeDef *acmp, uint32_t location, bool enable, bool invert)
	Sets up GPIO output from the ACMP. More...

void	ACMP_Init (ACMP_TypeDef acmp, const ACMP_Init_TypeDef init)
	Initialize ACMP. More...

__STATIC_INLINE void	ACMP_IntClear (ACMP_TypeDef *acmp, uint32_t flags)
	Clear one or more pending ACMP interrupts. More...

__STATIC_INLINE void	ACMP_IntDisable (ACMP_TypeDef *acmp, uint32_t flags)
	Disable one or more ACMP interrupts. More...

__STATIC_INLINE void	ACMP_IntEnable (ACMP_TypeDef *acmp, uint32_t flags)
	Enable one or more ACMP interrupts. More...

__STATIC_INLINE uint32_t	ACMP_IntGet (ACMP_TypeDef *acmp)
	Get pending ACMP interrupt flags. More...

__STATIC_INLINE uint32_t	ACMP_IntGetEnabled (ACMP_TypeDef *acmp)
	Get enabled and pending ACMP interrupt flags. Useful for handling more interrupt sources in the same interrupt handler. More...

__STATIC_INLINE void	ACMP_IntSet (ACMP_TypeDef *acmp, uint32_t flags)
	Set one or more pending ACMP interrupts from SW. More...

void	ACMP_Reset (ACMP_TypeDef *acmp)
	Reset ACMP to same state as after a HW reset. More...

Macro Definition Documentation

#define ACMP_CAPSENSE_INIT_DEFAULT

Value:

{                                                       \
  false,              /* fullBias */                    \
  false,              /* halfBias */                    \
  0x7,                /* biasProg */                    \
  acmpWarmTime512,    /* 512 cycle warmup to be safe */ \
  acmpHysteresisLevel5,                                 \
  acmpResistor3,                                        \
  false,              /* low power reference */         \
  0x3D,               /* VDD level */                   \
  true                /* Enable after init. */          \
}

Default config for capacitive sense mode initialization.

Definition at line 622 of file em_acmp.h.

Referenced by CAPSENSE_Init().

#define ACMP_INIT_DEFAULT

Value:

{                                                                           \
  false,              /* fullBias */                                        \
  false,              /* halfBias */                                        \
  0x7,                /* biasProg */                                        \
  false,              /* No interrupt on falling edge. */                   \
  false,              /* No interrupt on rising edge. */                    \
  acmpWarmTime512,    /* 512 cycle warmup to be safe */                     \
  acmpHysteresisLevel5,                                                     \
  false,              /* Disabled emitting inactive value during warmup. */ \
  false,              /* low power reference */                             \
  0x3D,               /* VDD level */                                       \
  true                /* Enable after init. */                              \
}

Default config for ACMP regular initialization.

Definition at line 749 of file em_acmp.h.

Enumeration Type Documentation

enum ACMP_CapsenseResistor_TypeDef

Resistor values used for the internal capacative sense resistor. See the datasheet for your device for details on each resistor value.

Enumerator
acmpResistor0	Resistor value 0
acmpResistor1	Resistor value 1
acmpResistor2	Resistor value 2
acmpResistor3	Resistor value 3

Definition at line 98 of file em_acmp.h.

enum ACMP_Channel_TypeDef

ACMP inputs. Note that scaled VDD and bandgap references can only be used as negative inputs.

Enumerator
acmpChannel0	Channel 0
acmpChannel1	Channel 1
acmpChannel2	Channel 2
acmpChannel3	Channel 3
acmpChannel4	Channel 4
acmpChannel5	Channel 5
acmpChannel6	Channel 6
acmpChannel7	Channel 7
acmpChannel1V25	1.25V internal reference
acmpChannel2V5	2.5V internal reference
acmpChannelVDD	Scaled VDD reference
acmpChannelDAC0Ch0	DAC0 channel 0
acmpChannelDAC0Ch1	DAC0 channel 1
acmpChannelCapSense	Capacitive sense mode

Definition at line 465 of file em_acmp.h.

enum ACMP_HysteresisLevel_TypeDef

Hysteresis level. See datasheet for your device for details on each level.

Enumerator
acmpHysteresisLevel0	Hysteresis level 0
acmpHysteresisLevel1	Hysteresis level 1
acmpHysteresisLevel2	Hysteresis level 2
acmpHysteresisLevel3	Hysteresis level 3
acmpHysteresisLevel4	Hysteresis level 4
acmpHysteresisLevel5	Hysteresis level 5
acmpHysteresisLevel6	Hysteresis level 6
acmpHysteresisLevel7	Hysteresis level 7

Definition at line 114 of file em_acmp.h.

enum ACMP_WarmTime_TypeDef

ACMP warmup time. The delay is measured in HFPERCLK cycles and should be at least 10 us.

Enumerator
acmpWarmTime4	4 HFPERCLK cycles warmup
acmpWarmTime8	8 HFPERCLK cycles warmup
acmpWarmTime16	16 HFPERCLK cycles warmup
acmpWarmTime32	32 HFPERCLK cycles warmup
acmpWarmTime64	64 HFPERCLK cycles warmup
acmpWarmTime128	128 HFPERCLK cycles warmup
acmpWarmTime256	256 HFPERCLK cycles warmup
acmpWarmTime512	512 HFPERCLK cycles warmup

Definition at line 149 of file em_acmp.h.

Function Documentation

void ACMP_CapsenseChannelSet	(	ACMP_TypeDef *	acmp,
		ACMP_Channel_TypeDef	channel
	)

Sets the ACMP channel used for capacative sensing.

Note: A basic example of capacative sensing can be found in the STK BSP (capsense demo).

Parameters

[in]	acmp	Pointer to ACMP peripheral register block.
[in]	channel	The ACMP channel to use for capacative sensing (Possel).

Definition at line 185 of file em_acmp.c.

References _ACMP_INPUTSEL_POSSEL_CH7, _ACMP_INPUTSEL_POSSEL_MASK, _ACMP_INPUTSEL_POSSEL_SHIFT, BUS_RegMaskedWrite(), and ACMP_TypeDef::INPUTSEL.

Referenced by CAPSENSE_Measure().

void ACMP_CapsenseInit	(	ACMP_TypeDef *	acmp,
		const ACMP_CapsenseInit_TypeDef *	init
	)

Sets up the ACMP for use in capacative sense applications.

This function sets up the ACMP for use in capacacitve sense applications. To use the capacative sense functionality in the ACMP you need to use the PRS output of the ACMP module to count the number of oscillations in the capacative sense circuit (possibly using a TIMER).

Note: A basic example of capacative sensing can be found in the STK BSP (capsense demo).

Parameters

[in]	acmp	Pointer to ACMP peripheral register block.
[in]	init	Pointer to initialization structure used to configure ACMP for capacative sensing operation.

Definition at line 109 of file em_acmp.c.

Referenced by CAPLESENSE_setupACMP(), and CAPSENSE_Init().

void ACMP_ChannelSet	(	ACMP_TypeDef *	acmp,
		ACMP_Channel_TypeDef	negSel,
		ACMP_Channel_TypeDef	posSel
	)

Sets which channels should be used in ACMP comparisons.

Parameters

[in]	acmp	Pointer to the ACMP peripheral register block.
	negSel	Channel to use on the negative input to the ACMP.
	posSel	Channel to use on the positive input to the ACMP.

Definition at line 340 of file em_acmp.c.

References _ACMP_INPUTSEL_NEGSEL_CAPSENSE, _ACMP_INPUTSEL_NEGSEL_DAC0CH1, _ACMP_INPUTSEL_NEGSEL_MASK, _ACMP_INPUTSEL_NEGSEL_SHIFT, _ACMP_INPUTSEL_POSSEL_CH7, _ACMP_INPUTSEL_POSSEL_MASK, _ACMP_INPUTSEL_POSSEL_SHIFT, and ACMP_TypeDef::INPUTSEL.

void ACMP_Disable ( ACMP_TypeDef * acmp )

Disables the ACMP.

Parameters

[in] acmp Pointer to ACMP peripheral register block.

Definition at line 210 of file em_acmp.c.

References ACMP_CTRL_EN, and ACMP_TypeDef::CTRL.

Referenced by CAPSENSE_Sense().

void ACMP_Enable ( ACMP_TypeDef * acmp )

Enables the ACMP.

Parameters

[in] acmp Pointer to ACMP peripheral register block.

Definition at line 225 of file em_acmp.c.

References ACMP_CTRL_EN, and ACMP_TypeDef::CTRL.

Referenced by CAPSENSE_Sense().

void ACMP_GPIOSetup	(	ACMP_TypeDef *	acmp,
		uint32_t	location,
		bool	enable,
		bool	invert
	)

Sets up GPIO output from the ACMP.

Note

GPIO must be enabled in the CMU before this function call, i.e.

CMU_ClockEnable(cmuClock_GPIO, true);

Parameters

[in]	acmp	Pointer to the ACMP peripheral register block.
	location	The pin location to use. See the datasheet for location to pin mappings.
	enable	Enable or disable pin output.
	invert	Invert output.

Definition at line 305 of file em_acmp.c.

References _ACMP_CTRL_GPIOINV_MASK, _ACMP_CTRL_GPIOINV_SHIFT, _ACMP_ROUTE_ACMPPEN_SHIFT, _ACMP_ROUTE_LOCATION_SHIFT, BUS_RegMaskedWrite(), ACMP_TypeDef::CTRL, and ACMP_TypeDef::ROUTE.

Referenced by CAPLESENSE_setupACMP().

void ACMP_Init	(	ACMP_TypeDef *	acmp,
		const ACMP_Init_TypeDef *	init
	)

Initialize ACMP.

Parameters

[in]	acmp	Pointer to the ACMP peripheral register block.
[in]	init	Pointer to initialization structure used to configure ACMP for capacative sensing operation.

Definition at line 374 of file em_acmp.c.

__STATIC_INLINE void ACMP_IntClear	(	ACMP_TypeDef *	acmp,
		uint32_t	flags
	)

Clear one or more pending ACMP interrupts.

Parameters

[in]	acmp	Pointer to ACMP peripheral register block.
[in]	flags	Pending ACMP interrupt source to clear. Use a bitwise logic OR combination of valid interrupt flags for the ACMP module. The flags can be for instance ACMP_IFC_EDGE or ACMP_IFC_WARMUP.

Definition at line 881 of file em_acmp.h.

References ACMP_TypeDef::IFC.

__STATIC_INLINE void ACMP_IntDisable	(	ACMP_TypeDef *	acmp,
		uint32_t	flags
	)

Disable one or more ACMP interrupts.

Parameters

[in]	acmp	Pointer to ACMP peripheral register block.
[in]	flags	ACMP interrupt sources to disable. Use a bitwise logic OR combination of valid interrupt flags for the ACMP module. The flags can be for instance ACMP_IEN_EDGE or ACMP_IEN_WARMUP.

Definition at line 899 of file em_acmp.h.

References ACMP_TypeDef::IEN.

__STATIC_INLINE void ACMP_IntEnable	(	ACMP_TypeDef *	acmp,
		uint32_t	flags
	)

Enable one or more ACMP interrupts.

Note: Depending on the use, a pending interrupt may already be set prior to enabling the interrupt. Consider using ACMP_IntClear() prior to enabling if such a pending interrupt should be ignored.

Parameters

[in]	acmp	Pointer to ACMP peripheral register block.
[in]	flags	ACMP interrupt sources to enable. Use a bitwise logic OR combination of valid interrupt flags for the ACMP module. The flags can be for instance ACMP_IEN_EDGE or ACMP_IEN_WARMUP.

Definition at line 922 of file em_acmp.h.

References ACMP_TypeDef::IEN.

__STATIC_INLINE uint32_t ACMP_IntGet ( ACMP_TypeDef * acmp )

Get pending ACMP interrupt flags.

Note: The event bits are not cleared by the use of this function.

Parameters

[in] acmp Pointer to ACMP peripheral register block.

Returns: ACMP interrupt sources pending. A bitwise logic OR combination of valid interrupt flags for the ACMP module. The pending interrupt sources can be for instance ACMP_IF_EDGE or ACMP_IF_WARMUP.

Definition at line 943 of file em_acmp.h.

References ACMP_TypeDef::IF.

__STATIC_INLINE uint32_t ACMP_IntGetEnabled ( ACMP_TypeDef * acmp )

Get enabled and pending ACMP interrupt flags. Useful for handling more interrupt sources in the same interrupt handler.

Parameters

[in] acmp Pointer to ACMP peripheral register block.

Note: Interrupt flags are not cleared by the use of this function.

Returns

Pending and enabled ACMP interrupt sources. The return value is the bitwise AND combination of

the OR combination of enabled interrupt sources in ACMPx_IEN_nnn register (ACMPx_IEN_nnn) and
the OR combination of valid interrupt flags of the ACMP module (ACMPx_IF_nnn).

Definition at line 968 of file em_acmp.h.

References ACMP_TypeDef::IEN, and ACMP_TypeDef::IF.

__STATIC_INLINE void ACMP_IntSet	(	ACMP_TypeDef *	acmp,
		uint32_t	flags
	)

Set one or more pending ACMP interrupts from SW.

Parameters

[in]	acmp	Pointer to ACMP peripheral register block.
[in]	flags	ACMP interrupt sources to set to pending. Use a bitwise logic OR combination of valid interrupt flags for the ACMP module. The flags can be for instance ACMP_IFS_EDGE or ACMP_IFS_WARMUP.

Definition at line 993 of file em_acmp.h.

References ACMP_TypeDef::IFS.

void ACMP_Reset ( ACMP_TypeDef * acmp )

Reset ACMP to same state as after a HW reset.

Note: The ROUTE register is NOT reset by this function, in order to allow for centralized setup of this feature.

Parameters

[in] acmp Pointer to the ACMP peripheral register block.

Definition at line 270 of file em_acmp.c.

References _ACMP_CTRL_RESETVALUE, _ACMP_IEN_RESETVALUE, _ACMP_IF_MASK, _ACMP_INPUTSEL_RESETVALUE, ACMP_TypeDef::CTRL, ACMP_TypeDef::IEN, ACMP_TypeDef::IFC, and ACMP_TypeDef::INPUTSEL.

Detailed Description

Data Structures

Macros

Enumerations

Functions

Macro Definition Documentation

Enumeration Type Documentation

Function Documentation